Composite member made of different resin

Abstract

To provide a composite member made of different resins that is excellent in strength, heat resistance, rigidity and assembly cycle property of a welded part.SOLUTION: In a composite member of different resins in which an acrylic resin member made of an acrylic resin composition and a styrene resin member made of a styrene resin composition having a Vicat softening temperature of 105°C or higher are welded together, the acrylic resin composition has a methyl methacrylate monomer unit content of more than 50 mass%, and the styrene resin composition has a styrene monomer unit content of more than 50 mass% and a methacrylic acid monomer unit content of 3 mass% or more, and a three-dimensional plot distance (HSP distance) between a Hansen solubility parameter (HSP) value of a chloroform-soluble matter of the styrene resin composition and the Hansen solubility parameter (HSP) value of the chloroform-soluble matter of the acrylic resin composition is 4.0 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a heterogeneous resin composite member in which an acrylic resin member made of an acrylic resin composition and a styrene resin member are welded together, and to a lighting housing and an in-vehicle member made of the heterogeneous resin composite member. [Background technology]

[0002] Styrene-unsaturated carboxylic acid resins, typified by styrene-methacrylic acid copolymer resins, are excellent in heat resistance, transparency, rigidity, and appearance, are inexpensive, and are easily reused by thermal decomposition into styrene monomer, resulting in excellent chemical recycling properties, and are therefore widely used in packaging materials for food containers such as lunch boxes and prepared dishes, foam boards for residential insulation, diffusion plates for LCD televisions containing a diffusing agent, etc. Therefore, future development is expected in applications requiring heat resistance, such as vehicle lighting fixtures such as headlamps, rear lamps, fog lamps, and turn lamps, or vehicle interior and exterior materials.

[0003] Patent Documents 1 and 2 are examples of technologies relating to materials used in vehicle lamps. Patent Document 1 discloses a technology relating to a vehicle lamp in which a lens molded product containing a methacrylic resin composition and a housing molded product made of an ASA resin, an ABS resin, an AES resin, an SAS resin, or an ACS resin are laser-welded together. Patent Document 2 describes a technology relating to a vehicle lamp in which a resin composition made of a methacrylic resin and a soft rubber phase is joined by heat welding to ABS resin, which is the material for the lamp body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2016 / 084545 [Patent Document 2] Japanese Patent Application Publication No. 7-282602 Summary of the Invention [Problem to be solved by the invention]

[0005] As described in the technology of Patent Document 1, laser welding is used as a means for joining a lamp lens molded product made of a methacrylic resin to a housing molded product made of an ASA resin, an ABS resin, an AES resin, an SAS resin, or an ACS resin. Also, in the technology of Patent Document 2, heat welding is used as a means for joining a lamp lens made of a resin composition in which a methacrylic resin is blended with a multilayer polymer containing a soft rubber layer to a lamp body mainly made of an ABS resin.

[0006] However, with the above technology, the welding strength between the lamp lens and lamp body is insufficient due to the compatibility between different resins, resulting in problems such as easy separation depending on the shape of the molded product and the welding method of the molded product. Furthermore, ASA-based resins, ABS-based resins, AES-based resins, SAS-based resins, and ACS-based resins lack heat resistance, raising concerns about problems such as thermal deformation. Furthermore, in response to the recent trend toward a recycling-oriented society, chemical recycling of resin materials is required. However, ABS resin is difficult to recycle due to the generation of cyanide gas, so alternatives to ABS resin are needed.

[0007] Therefore, the problem to be solved by the present invention is to provide a heterogeneous resin composite member having excellent strength, heat resistance, rigidity, and assembly cycle properties at the welded portion, as well as a lighting housing and an in-vehicle component made of the heterogeneous resin composite member. [Means for solving the problem]

[0008] The present inventors have conducted extensive research in light of the above problems, and as a result have succeeded in realizing a heterogeneous resin composite member that exhibits excellent strength, heat resistance, rigidity, and assembly cycle properties at the welded portion by achieving a specific relationship of Hansen Solubility Parameter (HSP) values ​​when welding an acrylic resin member made of an acrylic resin composition and a styrene resin member made of a styrene resin composition, as well as a lighting housing and an in-vehicle member using the same, thereby completing the present invention.

[0009] [1] The present disclosure provides a heterogeneous resin composite member in which an acrylic resin member made of an acrylic resin composition and a styrene resin member made of a styrene resin composition having a Vicat softening temperature of 105°C or higher are welded together, The acrylic resin composition has a content of methyl methacrylate monomer units of more than 50% by mass, The styrene-based resin composition has a content of styrene-based monomer units of more than 50% by mass and a content of methacrylic acid monomer units of 3% by mass or more, The Hansen solubility parameter (HSP) value (δ ds ,δ ps ,δ hs )(J / cm 3 ) 1 / 2 and the Hansen solubility parameter (HSP) value (δ da ,δ pa ,δ ha )(J / cm 3 ) 1 / 2 ] is a heterogeneous resin composite member in which the three-dimensional plot distance (HSP distance) between the [Number 1] HSP distance={(δ ds -δ da ) 2 +(δ ps -δ pa ) 2 +(δ hs -δ ha ) 2} 1 / 2 ≦4.0 (Formula (1)) (In the above formula (I), δ ds is the dispersion force term of the styrene resin composition (J / cm 3 ) 1 / 2 represents δ ps (J / cm 3 ) 1 / 2 represents the polarity term of the styrene-based resin composition, and δ hs (J / cm 3 ) 1 / 2 represents the hydrogen bond term of the styrene-based resin composition, and δ dais the dispersion force term of the acrylic resin composition (J / cm 3 ) 1 / 2 represents δ pa (J / cm 3 ) 1 / 2 represents the polarity term of the acrylic resin composition, and δ ha (J / cm 3 ) 1 / 2 represents the hydrogen bond term of the acrylic resin composition.

[0010] [2] The polar term (δ) of the Hansen solubility parameter of the methyl ethyl ketone soluble matter of the styrene-based resin composition ps ) and hydrogen bond term (δ hs ) and the sum is Sδ p+h year, The polarity value (δ) of the Hansen solubility parameter of the chloroform-soluble portion of the acrylic resin composition pa ) and hydrogen bond term (δ ha ) and the sum of Aδ p+h When the above definition is made, it is preferable to satisfy the following formula (2). |Sδ p+h -Aδ p+h |≦5.0···(Formula (2))

[0011] [3] The heterogeneous resin composite member according to [1] or [2], wherein the absolute value of the difference between the Vicat softening temperature of the styrene-based resin composition and the Vicat softening temperature of the acrylic resin composition is 30 or less.

[0012] [4] The heterogeneous resin composite material according to any one of [1] to [3], wherein the acrylic resin composition has a weight average molecular weight (Mw) of 70,000 to 300,000.

[0013] [5] The heterogeneous resin composite member according to any one of [1] to [4], wherein the acrylic resin member has a total light transmittance of 90% or more in an optical path length of 2 mm.

[0014] [6] The heterogeneous resin composite member according to any one of [1] to [5], wherein the styrene-based resin composition is composed mainly of a copolymer having styrene monomer units and methacrylic acid monomer units.

[0015] [7] The heterogeneous resin composite member according to any one of [1] to [6], wherein the styrene-based resin composition has a lightness (L*) of 50 or less.

[0016] [8] A heterogeneous resin composite member according to any one of [1] to [7], comprising the styrene-based resin member having a recess, and the acrylic-based resin member attached by welding near the edge of the recess.

[0017] [9] The heterogeneous resin composite member according to any one of [1] to [8], which is used as a lighting housing.

[0018]

[10] A rear lamp housing for use in a vehicle, which uses the composite member of different resins according to any one of [1] to [8]. [Effects of the Invention]

[0019] According to the present disclosure, it is possible to provide a composite member of different resins having excellent strength, heat resistance, rigidity, and assembly cycle properties at welded portions, and a lighting housing and an in-vehicle component using the composite member of different resins. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic view showing an example of an acrylic resin member and a styrene resin member before they are joined together. [Figure 2] FIG. 2 is a schematic diagram showing an example of a composite member of different resins in which an acrylic resin member and a styrene resin member are joined by welding. [Figure 3] FIG. 3 is a schematic diagram showing an embodiment in which the composite member of different resins according to the present embodiment is used in a rear lamp housing for a vehicle. [Figure 4] FIG. 4 is a schematic diagram of an example of a test piece of a composite member made of different resins in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. Note that the present invention is not limited to the following embodiment, and various modifications can be made within the scope of the gist of the present invention.

[0022] [Composite materials made from different resins] The heterogeneous resin composite member (hereinafter sometimes simply referred to as a composite member) in this embodiment is a heterogeneous resin composite member obtained by welding an acrylic resin member made of an acrylic resin composition and a styrene resin member made of a styrene resin composition having a Vicat softening temperature of 105° C. or higher. The acrylic resin composition has a methyl methacrylate monomer unit content of more than 50% by mass, and the styrene resin composition has a styrene monomer unit content of more than 50% by mass and a methacrylic acid monomer unit content of 3% by mass or higher. In addition, the Hansen solubility parameter (HSP) value (δ ds ,δ ps ,δ hs )(J / cm 3 ) 1 / 2 and the Hansen solubility parameter (HSP) value (δ da ,δ pa ,δ ha )(J / cm 3 ) 1 / 2 ] and the 3D plot distance (HSP distance) satisfies the following formula (1) [Number 1] HSP distance={(δ ds -δ da ) 2 +(δ ps -δ pa ) 2 +(δ hs -δ ha ) 2} 1 / 2 ≦4.0 (Formula 1) (In the above formula (I), δ ds is the dispersion force term of the styrene resin composition (J / cm 3 ) 1 / 2 represents δ ps (J / cm3 ) 1 / 2 represents the polarity term of the styrene-based resin composition, and δ hs (J / cm 3 ) 1 / 2 represents the hydrogen bond term of the styrene-based resin composition, and δ da is the dispersion force term of the acrylic resin composition (J / cm 3 ) 1 / 2 represents δ pa (J / cm 3 ) 1 / 2 represents the polarity term of the acrylic resin composition, and δ ha (J / cm 3 ) 1 / 2 represents the hydrogen bond term of the acrylic resin composition. This makes it possible to provide a composite member of different resins that is excellent in strength, heat resistance, rigidity, and assembly cycle properties of the welded portion.

[0023] The shape of the styrene-based resin member of this embodiment is not particularly limited, and any desired shape can be adopted depending on the intended use. For example, the shape of the styrene-based resin member may be a rod, a curved plate, a flat plate, a mesh, a semicircle, a semi-ellipse, a prism, a cone, a pyramid, or a combination thereof. A preferred shape of the styrene-based resin member is one having a recess (a so-called vessel shape). Similarly, the shape of the acrylic resin member of this embodiment is not particularly limited, and any desired shape can be adopted depending on the intended use. For example, the shape of the acrylic resin member can be a rod, a curved plate, a flat plate, a mesh, a semicircle, a semi-ellipse, a prism, a cone, a pyramid, or a combination thereof. A curved plate shape is preferred as the shape of the acrylic resin member from the viewpoint of bonding with the styrene-based resin member. When the styrene-based resin member is a member having a recess, the opening of the recess can be covered by the curved plate-shaped acrylic resin member, allowing a desired member or component to be accommodated in the recess, and the entire heterogeneous resin composite member can be used as a housing material.

[0024] Hereinafter, with reference to Figures 1 and 2, the structure of a heterogeneous resin composite member in which an acrylic resin member made of an acrylic resin composition and a styrene resin member made of a styrene resin composition having a Vicat softening temperature of 105°C or higher are welded together will be described. For convenience of explanation, FIGS. 1 and 2 show an embodiment in which a flat plate is used as an example of the acrylic resin member, and a container having a recess is used as an example of the styrene resin member. 1 and 2, the styrene resin member 22 has a recess of depth D2 × width W2 × predetermined depth, and is a rectangular parallelepiped with an edge width w0 and height H2. On the other hand, the acrylic resin member 33 has a flat plate shape of depth D1 × width W1 × predetermined thickness. The dissimilar resin composite member 11 of this embodiment has a container-shaped styrene-based resin member 22 having a recess and an acrylic-based resin member 33 covering the opening of the recess, and the acrylic-based resin member 33 is joined to the styrene-based resin member 22 by welding. More specifically, the flat plate-shaped acrylic-based resin member 33 and the edge of the styrene-based resin member 33 are hot-plate welded together, and then the two are joined by pressure-bonding. Therefore, in the example of the dissimilar resin composite member shown in Figures 1 and 2, the pressure-bonding direction can be the vertical direction in Figures 1 and 2.

[0025] In the heterogeneous resin composite member of this embodiment, the styrene-based resin member 22 formed from the styrene-based resin composition has a recessed portion and therefore an internal space. The styrene-based resin member 22 also has a concave main body portion with an opening and an annular edge portion protruding from the upper end side of the main body portion. The annular edge portion and a flat acrylic resin member 33 can be joined by welding to form the heterogeneous resin composite member.

[0026] "Welding" In this specification, welding refers to the process of joining multiple component parts together by heating or melting the joint of at least one component part, thereby fluidizing the joint and entangling molecules near the interface to ensure strength. Therefore, when joining an acrylic resin member and a styrene-based resin member, the welding portion (e.g., the surface portion to be joined) of at least one of the acrylic resin member and / or the styrene-based resin member is heated or melted, and, if necessary, contact pressure and / or cooling is further applied to the joint, resulting in a joined state due to entanglement caused by diffusion of polymer molecules constituting the acrylic resin member and / or the styrene-based resin member, or due to entanglement and crystallization of the polymer molecules caused by diffusion. The method for welding the styrene-based resin member and the acrylic-based resin member in this embodiment is not particularly limited, and various welding methods can be used. Examples of such welding methods include one or more methods selected from a group consisting of laser welding, vibration welding, spin welding, high-frequency welding, ultrasonic welding, and heat welding (including hot plate welding, hot air welding, iron welding, and frictional heat). Among these, the method for welding the heterogeneous resin composite member consisting of the styrene-based resin member and the acrylic-based resin member in this embodiment is preferably one selected from the group consisting of heat welding, laser welding, vibration welding, ultrasonic welding, spin welding, and high-frequency welding, with heat welding being more preferred. Heat welding methods include contact welding, in which a hot plate is applied to the resin to melt it, and non-contact welding, in which the resin is melted using radiant heat from the hot plate. A preferred welding method in this embodiment may be hot plate welding.

[0027] <High frequency welding> Examples of the high-frequency welding include a welding method in which an object to be heated is heated from the inside by using the electric field action of high-frequency (electromagnetic wave) energy. In this embodiment, high-frequency welding can be performed by either one-shot welding using a high-frequency welder or continuous welding using a high-frequency sewing machine. The conditions for the high-frequency welding are not particularly limited and may be any known conditions, such as an oscillation frequency of 30 to 50 MHz, an oscillation time of 1 to 3 seconds, and an anode current value of 1 to 30 A.

[0028] <Ultrasonic welding> The ultrasonic welding method involves transmitting ultrasonic vibrations from a resonator (horn) to an object to be heated and joining the object by the frictional heat generated inside. More specifically, the resonator is pressed against an acrylic resin member and / or a styrene resin member, applying high-frequency mechanical vibrations from the resonator to the member, which are converted into frictional heat. The frictional heat melts the member, forming a weld, and the member is welded to the object. Ultrasonic welding can be performed by placing the surface of the first member (either the acrylic resin member or the styrene resin member) on which the energy director is provided face to face with the surface of the second member (the other of the acrylic resin member or the styrene resin member) to be welded, pressing a welding horn against the reinforcing member to apply high-frequency vibrations and melt the energy director, and then solidifying the molten energy director by cooling, thereby forming a welded portion.

[0029] From the viewpoint of welding strength and the appearance of the composite member, when welding the energy director to the resin molded product, it is preferable to press the energy director against the acrylic resin member and the styrene resin member with a load of 10 N to 300 N. The load is more preferably 10 N to 200 N, and even more preferably 20 N to 180 N. The amplitude of the welding is not particularly limited and can be, for example, 1 μm to 100 μm. The welding time is not particularly limited and can be, for example, 0.1 seconds to 30 seconds.

[0030] The welding horn preferably vibrates from one end of the first member to the other, or from the center toward both ends. By performing ultrasonic welding using the above method, it is possible to prevent a gap from forming between the acrylic resin member and the styrene resin member, which would otherwise reduce the welding strength. Ultrasonic welding using the above method is particularly preferred when the acrylic resin member has a curved shape and the styrene resin member has a flexural modulus of elasticity of 900 MPa to 1700 MPa, as the flexibility of the styrene resin member allows it to easily conform to the shape of the acrylic resin member. When there is a gap (1 mm or less) between the first and second members, the ultrasonic welding of the above embodiment tends to be particularly effective.

[0031] In a structure in which either the acrylic resin member or the styrene-based resin member is bent, either the acrylic resin member or the styrene-based resin member may be cooled at least either before or during welding of the two members. By cooling either the acrylic resin member or the styrene-based resin member, the flexural modulus can be improved, and when welding the other member to the bent member, the energy director can more easily suppress deformation of the bent member, tending to form a composite member with excellent weld strength. From the viewpoint of maintaining good welding strength and the appearance of the bent member, the bent member is preferably cooled so that the temperature of the bent member is 3°C to 19°C, more preferably 5°C to 15°C. The cooling method is not particularly limited, and may be a conventionally known method such as air cooling, water cooling, etc. From the viewpoint of productivity of the composite member, it is preferable to cool the reinforcing member by applying cold air thereto.

[0032] <Hot plate welding> There are two types of hot plate welding: contact and non-contact. The contact type involves sandwiching a heated plate between an acrylic resin member and a styrene resin member, heating the surfaces to be welded, and then joining the acrylic resin member and the styrene resin member. Specific examples of contact type hot plate welding include the following: A hot plate is heated to a predetermined surface temperature (e.g., 200 to 300°C, particularly 250°C) using a hot plate welding machine (manufactured by Takagi Seiko Corporation). The hot plate is made of metal (e.g., aluminum) with a Teflon (registered trademark) surface. Then, a test piece having a surface of a predetermined size (20 mm × 2 mm) is pressed against the hot plate at a predetermined speed (for example, in the range of 0.1 to 10 mm / s, particularly 1 mm / s) so that it abuts on the surface, and is pressed down to a predetermined length (for example, 1.0 ± 0.5 mm) from the contact position, and after contact for, for example, 3 to 30 seconds, the test piece is released at a speed in the range of 20 ± 10 mm / s to join the acrylic resin member and the styrene resin member. Examples of non-contact hot plate welding include the following method. Specifically, a metal hot plate is used to heat the joining surfaces of the acrylic resin member and the styrene resin member in a non-contact state using radiant heat from the hot plate, without directly contacting the acrylic resin member and the styrene resin member, to melt the acrylic resin member and the styrene resin member, and then the two members are pressure-bonded together. The temperature of the hot plate is preferably 450 to 600°C, the distance between the hot plate and the joining surfaces of the acrylic resin member and the styrene resin member is preferably 0.2 to 2.0 mm, and the heating time is preferably 5 to 30 seconds.

[0033] <Hot air welding> The hot air welding method includes a method in which hot air is blown onto the joining portions of the acrylic resin members and / or styrene resin members, and pressure welding is performed using a roller (see, for example, JP 2014-217434 A).

[0034] The iron welding method includes a method of heating with an iron (heating plate) and applying pressure and welding with a roller. As a method of bonding by frictional heat, spin welding is a method in which the surfaces of the objects to be welded are brought together and fused and welded by the frictional heat generated by rotating them at high speed.

[0035] As described above, since the acrylic resin member and the styrene resin member are joined by welding, strength is maintained by the entanglement of the molecules of the components of the acrylic resin composition constituting the acrylic resin member and the molecules of the components of the styrene resin composition constituting the styrene resin member. Therefore, the compatibility of the components of the acrylic resin composition and the components of the styrene resin composition greatly affects the joining (or welding) strength. Therefore, the Hansen solubility parameter (HSP) value (δ) of the chloroform-soluble portion of the styrene resin composition ds ,δ ps ,δ hs )(J / cm 3 ) 1 / 2 and the Hansen solubility parameter (HSP) value (δ da ,δ pa ,δ ha )(J / cm 3 ) 1 / 2 It is believed that by making the three-dimensional plot distance (HSP distance) between the acrylic resin member and the styrene resin member satisfy the following formula (1), it is possible to provide a heterogeneous resin composite member that has excellent strength, heat resistance, rigidity, and assembly cycle properties at the welded joint between the acrylic resin member and the styrene resin member. [Number 1] HSP distance={(δ ds -δ da ) 2 +(δ ps -δ pa ) 2 +(δ hs -δ ha ) 2} 1 / 2 ≦4.0 (Formula 1) (In the above formula (I), δ ds is the dispersion force term of the styrene resin composition (J / cm 3 ) 1 / 2 represents δ ps (J / cm 3 ) 1 / 2 represents the polarity term of the styrene-based resin composition, and δhs (J / cm 3 ) 1 / 2 represents the hydrogen bond term of the styrene-based resin composition, and δ da is the dispersion force term of the acrylic resin composition (J / cm 3 ) 1 / 2 represents δ pa (J / cm 3 ) 1 / 2 represents the polarity term of the acrylic resin composition, and δ ha (J / cm 3 ) 1 / 2 represents the hydrogen bond term of the acrylic resin composition. Therefore, the Hansen Solubility Parameter (HSP) value (hereinafter simply referred to as the HSP value), which is an index showing the compatibility between an acrylic resin member and a styrene resin member, will be explained below.

[0036] "Hansen Solubility Parameter (HSP) value" The HSP value in the present disclosure is a value calculated by the Hansen sphere method based on the solubility evaluation of each resin and resin composition in an organic solvent with a known HSP value, and the dispersion component δ d , polar component δ p , hydrogen bond component δ h , and is a parameter consisting of three-dimensional components. A detailed evaluation method will be described in the Examples below, but it cannot be used to evaluate "insoluble components" such as crosslinked polymers and inorganic components that are insoluble in any organic solvent that may be contained in the resin used and the styrene-based resin composition. When such "insoluble components" are contained, the present disclosure will be explained using the HSP value of the chloroform-soluble components.

[0037] As described above, the heterogeneous resin composite member of the present disclosure comprises a styrene-based resin member obtained by molding the styrene-based resin composition and an acrylic-based resin member obtained by molding the acrylic-based resin composition, and the styrene-based resin composition has a Hansen solubility parameter (HSP) value (δ ds ,δ ps ,δ hs )(J / cm 3 ) 1 / 2and the Hansen solubility parameter (HSP) value (δ da ,δ pa ,δ ha )(J / cm 3 ) 1 / 2 The three-dimensional plot distance (HSP distance) between the styrene-based resin member and the acrylic-based resin member is 4.0 or less, and more preferably 3.8 or less, 3.6 or less, 3.4 or less, 3.2 or less, 3.0 or less, 2.8 or less, and 2.5 or less. By making it 3.0 or less in particular, a heterogeneous resin composite member having high interfacial strength between the styrene-based resin member and the acrylic-based resin member can be obtained.

[0038] In the Hansen solubility parameter (HSP) value of the chloroform-soluble component of the styrene-based resin composition, the dispersing component (δ ds ) value is 15 to 20 (J / cm 3 ) 1 / 2 is preferably in the range of 16 to 19 (J / cm 3 ) 1 / 2 in the range of 17 to 18 (J / cm 3 ) 1 / 2 The range of the polar component (δ ps ) values ​​are 5 to 12 (J / cm 3 ) 1 / 2 is preferably in the range of 6 to 11 (J / cm 3 ) 1 / 2 in the range of 8 to 10 (J / cm 3 ) 1 / 2 The range of the hydrogen bonding component (δ hs ) values ​​are 3 to 9 (J / cm 3 ) 1 / 2 is preferably in the range of 5 to 8 (J / cm 3 ) 1 / 2 in the range of 6 to 7 (J / cm 3 ) 1 / 2 The range is preferred.

[0039] In the Hansen solubility parameter (HSP) value of the chloroform-soluble component of the acrylic resin composition, the dispersing component (δ da ) values ​​are 15 to 22 (J / cm 3 )1 / 2 is preferably in the range of 16 to 21 (J / cm 3 ) 1 / 2 more preferably in the range of 17 to 20 (J / cm 3 ) 1 / 2 The range of the polar component (δ pa ) values ​​are 7 to 14 (J / cm 3 ) 1 / 2 is preferably in the range of 8 to 13 (J / cm 3 ) 1 / 2 in the range of 9 to 12 (J / cm 3 ) 1 / 2 The range of the hydrogen bonding component (δ ha ) values ​​are 3 to 9 (J / cm 3 ) 1 / 2 is preferably in the range of 5 to 8 (J / cm 3 ) 1 / 2 in the range of 6 to 7 (J / cm 3 ) 1 / 2 The range is preferred.

[0040] In the Hansen solubility parameter (HSP) value of the chloroform-soluble portion of the styrene-based resin composition, the polar term (δ ps ) and hydrogen bond term (δ hs ) and the sum is Sδ p+h When the value is 10 to 20 (J / cm 3 ) 1 / 2 is preferably in the range of 12 to 18 (J / cm 3 ) 1 / 2 in the range of 14 to 16 (J / cm 3 ) 1 / 2 The range is.

[0041] In the Hansen Solubility Parameter (HSP) value of the chloroform-soluble portion of the acrylic resin composition, the polar term (δ pa ) and hydrogen bond term (δ ha ) and the sum is Aδ p+h When the value is 10 to 20 (J / cm 3 ) 1 / 2is preferably in the range of 13 to 19 (J / cm 3 ) 1 / 2 in the range of 15 to 18 (J / cm 3 ) 1 / 2 The range is.

[0042] The Sδ p+h and Aδ p+h Absolute value of the difference between |Sδ p+h -Aδ p+h The value of | is preferably 5.0 or less, and more preferably 4.8 or less, 4.6 or less, 4.4 or less, 4.2 or less, 4.0 or less, 3.8 or less, 3.6 or less, 3.4 or less, 3.2 or less, 3.0 or less, 2.8 or less, 2.6 or less, and 2.4 or less in that order. Among the Hansen solubility parameters (HSP) of the chloroform-soluble matter of the acrylic resin composition, the polar term (δ pa ) and hydrogen bond term (δ ha ) and the sum is Aδ p+h and the polarity term (δ) of the Hansen solubility parameter (HSP) of the chloroform-soluble matter of the styrene-based resin composition. ps ) and hydrogen bond term (δ hs ) and the sum is Sδ p+h When the absolute value of the difference is within the above range, a composite member of different resins having superior strength, heat resistance, rigidity and assembly cycle properties at the welded portion can be obtained.

[0043] <<Difference in Vicat softening temperature (℃) between acrylic resin composition and styrene resin composition>> The absolute value of the difference in Vicat softening temperature (°C) between the acrylic resin composition constituting the acrylic resin member and the styrene resin composition constituting the styrene resin member is preferably 30°C or less, more preferably 25°C or less, even more preferably 22°C or less, still more preferably 20°C or less, particularly preferably 18°C ​​or less, and most preferably 15°C or less. The Vicat softening temperature (°C) is measured in accordance with ISO 306 under conditions of a 5 kg load and a temperature rise rate of 50°C / hour. By setting the Vicat softening temperature difference within the above range, the melting conditions of the acrylic resin member and the styrene resin member can be matched, and a heterogeneous resin composite member having excellent interfacial strength when welded can be obtained.

[0044] The acrylic resin composition constituting the acrylic resin member and the styrene resin composition constituting the styrene resin member will be described in detail below.

[0045] "Acrylic resin composition" The acrylic resin composition in this embodiment is a resin composition that constitutes an acrylic resin member, and is a resin composition that essentially contains methyl methacrylate monomer units.

[0046] In this specification, the term "methyl methacrylate monomer unit" refers to a repeating unit constituting a polymer formed by polymerizing methyl methacrylate monomer, and is a repeating unit (or structural unit) in which the carbon-carbon double bond in the methyl methacrylate monomer becomes a single bond (-CC-) through a polymerization reaction or crosslinking reaction of the methyl methacrylate monomer. Other monomer units in this specification (e.g., styrene-based monomer units and methacrylic acid monomer units described below) have the same meaning.

[0047] The content of the methyl methacrylate monomer unit in the acrylic resin composition is more than 50% by mass relative to the entire acrylic resin composition (100% by mass), with the lower limit being preferably 60% by mass or more, 70% by mass or more, 80% by mass or more, 82% by mass or more, 84% by mass or more, 86% by mass or more, 88% by mass or more, 90% by mass or more, and the upper limit being preferably 100% by mass or less, 99% by mass or less, and 98.5% by mass or less. In particular, by setting the content of the methyl methacrylate monomer unit to 80% by mass or more, an acrylic resin member having excellent weldability with a styrene-based resin member made of a styrene-based resin composition described below, as well as excellent rigidity and mechanical strength can be provided.

[0048] <Preferred Form of Acrylic Resin Composition> In a preferred embodiment of the acrylic resin composition of the present invention, the main component constituting the acrylic resin composition is a copolymer (A) having methyl methacrylate monomer units and acrylic ester monomer units (hereinafter simply referred to as copolymer (A)). The "main component" constituting the acrylic resin composition means that the copolymer having methyl methacrylate monomer units and acrylic ester monomer units accounts for more than 50% by mass of the entire styrene resin composition (100% by mass).

[0049] In the Hansen Solubility Parameter (HSP) value of the copolymer (A) having the methyl methacrylate monomer unit and the acrylic acid ester monomer unit, the dispersion component (δ ds ) values ​​are 16 to 22 (J / cm 3 ) 1 / 2 is preferably in the range of 17 to 21 (J / cm 3 ) 1 / 2 in the range of 18 to 20 (J / cm 3 ) 1 / 2 The range of the polar component (δ) of the copolymer (i) is preferably ps ) values ​​are 8 to 14 (J / cm 3 ) 1 / 2 is preferably in the range of 9 to 13 (J / cm 3 ) 1 / 2 in the range of 10 to 12 (J / cm 3 ) 1 / 2 The range of the hydrogen bonding component (δ) of the copolymer (i) is preferably hs ) values ​​are 3 to 9 (J / cm 3 ) 1 / 2 is preferably in the range of 4 to 8 (J / cm 3 ) 1 / 2 in the range of 5 to 7 (J / cm 3 ) 1 / 2 The range is preferred.

[0050] The content of the copolymer (A) in the acrylic resin composition is preferably more than 50% by mass, more preferably 80% by mass or more, even more preferably 90% by mass or more, still more preferably 96% by mass or more, even more preferably 97% by mass or more, still more preferably 98% by mass or more, and most preferably 99% by mass or more, based on the total acrylic resin composition (100% by mass). The upper limit of the content of the copolymer (A) in the acrylic resin composition may be 100% by mass or less or less than 100% by mass. The content of the copolymer (A) in the acrylic resin composition is preferably more than 50% by mass and 100% by mass or less.

[0051] The lower limit of the content of methyl methacrylate monomer units in copolymer (A) containing methyl methacrylate monomer units and acrylic ester monomer units is preferably 60% by mass or more, and may be 70% by mass or more, 80% by mass or more, 82% by mass or more, 84% by mass or more, 86% by mass or more, 88% by mass or more, or 90% by mass or more, based on the entire copolymer (A) (100% by mass). On the other hand, the upper limit of the content of methyl methacrylate monomer units may be less than 100% by mass or 98.5% by mass or less. Furthermore, particularly preferred ranges for the content of methyl methacrylate monomer units are 90% by mass or more to 99.5% by mass or less, 92% by mass or more to 99.0% by mass or less, and 93% by mass or more to 98.5% by mass, in that order.

[0052] The acrylic acid ester monomer units impart thermal decomposition resistance to the copolymer (A), and specific examples thereof include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, pentyl acrylate, hexyl acrylate, cyclohexyl acrylate, heptyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, benzyl acrylate, etc. Methyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate are preferred from the viewpoint of industrial availability, and methyl acrylate is more preferred from the viewpoint of heat resistance.

[0053] As described above, the preferred form of the copolymer (A) having methyl methacrylate monomer units and acrylic acid ester monomer units is a copolymer having methyl methacrylate monomer units and methyl acrylate monomer units. In this case, the content of the methyl acrylate monomer units is preferably 0.1% by mass or more, based on the total amount (100% by mass) of the copolymer (A), and is more preferably 0.3% by mass to 15% by mass, 0.5% by mass to 10% by mass, 0.7% by mass to 8% by mass, 0.9% by mass to 7% by mass, and 1.2% by mass to 6% by mass in this order. By setting the content within the above range, an acrylic resin composition and an acrylic resin member having an excellent balance between heat resistance and thermal decomposition resistance can be obtained.

[0054] When copolymer (A) contains other monomer units other than methyl methacrylate monomer units and acrylic ester monomer units, the content thereof is preferably 15% by mass or less, more preferably 7% by mass or less, even more preferably 5% by mass or less, still more preferably 3% by mass or less, and most preferably 1% by mass or less, relative to the total amount (100% by mass) of copolymer (A).

[0055] The acrylic resin composition of the present embodiment may contain any additive components described below as needed within the range that does not impair the performance.

[0056] The weight average molecular weight (Mw) of the acrylic resin composition in this embodiment, in terms of standard polystyrene, is preferably 50,000 to 400,000, more preferably 60,000 to 350,000, even more preferably 70,000 to 300,000, and still more preferably 80,000 to 250,000. When the weight average molecular weight is 50,000 to 400,000, an acrylic resin composition having an excellent practical balance between strength and fluidity can be obtained.

[0057] The Vicat softening temperature of the acrylic resin composition in this embodiment is preferably 100°C or higher, more preferably 102°C or higher, even more preferably 104°C or higher, and even more preferably 106°C or higher. By adjusting the Vicat softening temperature of the acrylic resin composition to 100°C or higher, a heterogeneous resin composite member with excellent heat resistance can be obtained. The Vicat softening temperature in this specification can be measured in accordance with ISO 306 under conditions of a 5 kg load and a heating rate of 50°C / hour.

[0058] The melt flow rate of the acrylic resin composition in this embodiment at 230°C is preferably 0.2 to 4.0, more preferably 0.3 to 3.5, and even more preferably 0.4 to 3.0. A melt flow rate of 0.2 or more is preferred from the viewpoint of fluidity, and a melt flow rate of 4.0 or less is preferred from the viewpoint of the mechanical strength of the resin. The melt flow rate of the acrylic resin composition in the present disclosure is a value measured in accordance with ISO 1133 at 230°C under a load of 3.8 kg.

[0059] The total light transmittance (optical path length 2 mm) of the acrylic resin composition in this embodiment is preferably 80% or more, more preferably 85% or more, even more preferably 88% or more, still more preferably 90% or more, and most preferably 92% or more.

[0060] The yellowness index YI (optical path length 2 mm) of the acrylic resin composition in this embodiment is preferably 2 or less, more preferably 1 or less, even more preferably 0.8 or less, and still more preferably 0.6 or less.

[0061] "Styrene-based resin composition" The styrene-based resin composition of this embodiment is a resin composition that constitutes a styrene-based resin member and is a resin composition that essentially contains styrene-based monomer units and methacrylic acid monomer units. Furthermore, the styrene-based resin composition of this embodiment may contain the above-mentioned copolymer (A) having methyl methacrylate monomer units and acrylic acid ester monomer units, if necessary. When the styrene-based resin composition of this embodiment contains the copolymer (A), the content of the copolymer (A) is preferably 5% by mass or more and 40% by mass or less, and more preferably 8% by mass or more and 30% by mass or less, based on the total styrene-based resin composition.

[0062] <Styrene-based monomer unit> In the present embodiment, the styrene-based monomer is not particularly limited, but examples thereof include styrene, α-methylstyrene, β-methylstyrene, paramethylstyrene, orthomethylstyrene, metamethylstyrene, chlorostyrene, and bromostyrene. From an industrial viewpoint, styrene and α-methylstyrene are particularly preferred, and styrene is more preferred. The styrene-based monomer may be any of these alone or a mixture of two or more of them.

[0063] When two or more styrene-based monomers are used in combination, the mixture of styrene-based monomers preferably contains styrene. In this case, the lower limit of the styrene content in the mixture of styrene-based monomers is preferably 90.0% by mass or more, more preferably 95.0% by mass or more, even more preferably 99.0% by mass or more, even more preferably 99.5% by mass or more, and most preferably 99.9% by mass or more. The upper limit of the styrene content is preferably 100% by mass or less, more preferably less than 100% by mass. By making the styrene content in the styrene-based monomers 90.0% by mass or more, it is easy to control the polymerization reaction in an industrial process during the production of a styrene-based resin composition, and a high polymerization conversion rate can be maintained. The upper and lower limits may be any combination of values ​​as appropriate.

[0064] In this specification, the term "styrene monomer unit" refers to a repeating unit constituting a polymer obtained by polymerizing a styrene monomer, and is a repeating unit (or structural unit) in which the carbon-carbon double bond in the styrene monomer becomes a single bond (-CC-) through a polymerization reaction or crosslinking reaction of the styrene monomer. Other monomer units in this specification (e.g., methyl methacrylate monomer unit, methacrylic acid monomer unit, etc.) have the same meaning.

[0065] The content of the styrene-based monomer unit in the styrene-based resin composition is more than 50% by mass, preferably more than 53% by mass and not more than 95% by mass, more preferably more than 56% by mass and not more than 90% by mass, even more preferably more than 60% by mass and not more than 85% by mass, and still more preferably more than 63% by mass and not more than 80% by mass, relative to the entire styrene-based resin composition (100% by mass). In particular, by setting the content of the styrene-based monomer unit in the styrene-based resin composition to the range of more than 53% by mass and not more than 90% by mass, a styrene-based resin member having excellent welding strength with an acrylic resin member described below can be provided.

[0066] <Methacrylic acid monomer unit> The methacrylic acid monomer units in the styrene-based resin composition improve heat resistance and weldability with an acrylic resin member. The content of the methacrylic acid monomer units in the styrene-based resin composition is 3% by mass or more, more preferably 4% by mass or more to 30% by mass or less, more preferably 5% by mass or more to 20% by mass or less, even more preferably 6% by mass or more to 15% by mass or less, and even more preferably 6.5% by mass or more to 12% by mass or less, relative to the entire styrene-based resin composition (100% by mass). In particular, by setting the content of the methacrylic acid monomer units in the styrene-based resin composition in the range of 6% by mass or more to 15% by mass or less, a styrene-based resin member having excellent heat resistance and excellent weld strength with an acrylic resin member can be provided.

[0067] <Preferred Form of Styrene-Based Resin Composition> In a preferred embodiment of the styrene-based resin composition of the present invention, the main component constituting the styrene-based resin composition is a copolymer (S) having styrene-based monomer units and methacrylic acid monomer units (hereinafter, also simply referred to as copolymer (S)). The "main component" constituting the styrene-based resin composition means that the copolymer having styrene-based monomer units and methacrylic acid monomer units accounts for more than 50% by mass of the entire styrene-based resin composition (100% by mass).

[0068] In the Hansen solubility parameter (HSP) value of the copolymer (S) having the styrene monomer unit and the methacrylic acid monomer unit, the dispersion component (δ ds ) values ​​are 15 to 21 (J / cm 3 ) 1 / 2 is preferably in the range of 16 to 20 (J / cm 3 ) 1 / 2 in the range of 17 to 19 (J / cm 3 ) 1 / 2 The range of the polar component (δ ps ) values ​​are 5 to 12 (J / cm 3 ) 1 / 2 is preferably in the range of 6 to 11 (J / cm 3 ) 1 / 2 in the range of 7 to 10 (J / cm 3 ) 1 / 2 The range of the hydrogen bonding component (δ hs ) values ​​are 3 to 9 (J / cm 3 ) 1 / 2 is preferably in the range of 4 to 8 (J / cm 3 ) 1 / 2 in the range of 5 to 7 (J / cm 3 ) 1 / 2 The range is preferred.

[0069] The lower limit of the content of copolymer (S) in the styrene-based resin composition is preferably more than 50% by mass, more preferably more than 53% by mass, even more preferably more than 56% by mass, even more preferably more than 59% by mass, and most preferably more than 62% by mass, based on the total styrene-based resin composition (100% by mass). The upper limit of the content of copolymer (S) in the styrene-based resin composition may be 100% by mass or less, 98% by mass or less, 95% by mass or less, or 90% by mass or less. The upper and lower limits can be arbitrarily combined.

[0070] The content of styrene-based monomer units in copolymer (S) is preferably 50 to 97% by mass, more preferably 60 to 95% by mass, even more preferably 70 to 93% by mass, even more preferably 75 to 90% by mass, and most preferably 80 to 88% by mass, relative to the total amount (100% by mass) of copolymer (S). By setting the content of styrene-based monomer units to 50% by mass or more, copolymer (S) with excellent moldability can be obtained, and by setting it to 97% by mass or less, the heat resistance improvement effect of the methacrylic acid monomer units described below can be obtained. In particular, by setting the content of styrene-based monomer units in the range of 75 to 90% by mass, copolymer (S) with an excellent balance between moldability and heat resistance can be obtained.

[0071] The content of methacrylic acid monomer units in copolymer (S) is preferably 3 to 30% by mass, more preferably 5 to 25% by mass, even more preferably 7 to 20% by mass, even more preferably 9 to 17% by mass, and most preferably 10 to 15% by mass, relative to the total amount (100% by mass) of copolymer (S). By setting the content of methacrylic acid monomer units to 3% by mass or more, it is possible to obtain an improved heat resistance, and by setting it to 30% by mass or less, it is possible to obtain copolymer (S) with excellent fluidity. In particular, by setting the content of methacrylic acid monomer units in the range of 7 to 20% by mass, it is possible to obtain a styrene-based resin composition with an excellent balance between weldability with acrylic and moldability.

[0072] When producing the copolymer (S), monomers other than the styrene-based monomer and the methacrylic acid monomer may also be copolymerized as needed. Examples of such monomers include (meth)acrylic acid ester monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and decyl (meth)acrylate, as well as maleic anhydride, maleic acid, fumaric acid, itaconic acid, (meth)acrylonitrile, dimethyl maleate, dimethyl fumarate, diethyl fumarate, ethyl fumarate, maleimide, nucleus-substituted maleimide, and α-methylstyrene. In particular, from the viewpoint of improving the weldability with acrylic resin members, it is preferable to copolymerize a (meth)acrylic acid ester monomer, and from the viewpoint of industrial availability, methyl (meth)acrylate, butyl (meth)acrylate, n-octyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate are more preferable. From the viewpoint of improving weldability, methyl methacrylate is most preferred, that is, the copolymer (S) is preferably a styrene-methacrylic acid-methyl methacrylate copolymer.

[0073] When copolymer (S) contains methyl methacrylate monomer units, the content of the methyl methacrylate monomer units is preferably 1 to 30 mass%, more preferably 2 to 20 mass%, even more preferably 3 to 17 mass%, and even more preferably 4 to 15 mass%, relative to the total amount (100 mass%) of copolymer (S). In particular, by containing methyl methacrylate monomer units in the range of 3 to 17 mass%, a styrene resin composition having an excellent balance between moldability and weldability to acrylic resin members can be provided.

[0074] When the copolymer (S) contains other monomer units other than styrene-based monomer units, methacrylic acid monomer units, and methyl methacrylate monomer units, the content thereof is preferably 10% by mass or less, more preferably 7% by mass or less, even more preferably 5% by mass or less, and even more preferably 3% by mass or less.

[0075] The styrene-based resin composition of the present invention may contain optional additives described below, or core-shell rubber, high-impact polystyrene, styrene-based elastomer, acrylic elastomer, or other resins for the purpose of improving impact strength, as long as the properties are not impaired. In order to improve weldability with acrylic resin, the core-shell rubber preferably contains a (meth)acrylic acid ester monomer. When high-impact polystyrene is used, in order to improve the weldability with the acrylic resin composition, the matrix phase preferably contains 10% or more of (meth)acrylic acid ester monomer, more preferably 20% or more, more preferably 25% or more, more preferably 30% or more, more preferably 35% or more, and more preferably 40% or more. Also, it is preferable that a copolymer containing a (meth)acrylic acid ester monomer is bonded to the rubber-like polymer particles contained in the high-impact polystyrene.

[0076] The lightness (L*) of the styrene resin composition is preferably 50 or less, more preferably 5 to 45, even more preferably 7 to 40, still more preferably 10 to 37, and most preferably in the range of 15 to 35.

[0077] The weight average molecular weight (Mw) of the styrene-based resin composition in this embodiment, in terms of standard polystyrene, is preferably 100,000 to 400,000, more preferably 120,000 to 300,000, even more preferably 140,000 to 280,000, and still more preferably 170,000 to 230,000. When the weight average molecular weight is 100,000 to 400,000, a styrene-based resin composition having an excellent practical balance between impact strength and fluidity can be obtained.

[0078] The Vicat softening temperature of the styrene-based resin composition in this embodiment is 105°C or higher, more preferably 107°C or higher, even more preferably 109°C or higher, and even more preferably 110°C or higher. By adjusting the Vicat softening temperature of the styrene-based resin composition to 105°C or higher, a heterogeneous resin composite member with excellent heat resistance can be obtained. The Vicat softening temperature in this specification can be measured in accordance with ISO 306 under conditions of a 5 kg load and a heating rate of 50°C / hour.

[0079] The melt flow rate of the styrene-based resin composition in this embodiment at 200°C may be preferably 0.2 to 4.0, more preferably 0.3 to 3.5, and even more preferably 0.4 to 3.0. A melt flow rate of 0.2 or more is preferred from the viewpoint of fluidity, and a melt flow rate of 4.0 or less is preferred from the viewpoint of the mechanical strength of the resin. In the present disclosure, the melt flow rate is a value measured in accordance with ISO 1133 at 200°C under a load of 5 kg.

[0080] In this embodiment, the content of styrene-based monomer (residue) contained in the styrene-based resin composition is preferably 3000 μg / g or less, more preferably 2000 μg / g or less, even more preferably 1500 μg / g or less, even more preferably 1000 μg / g or less, even more preferably 900 μg / g or less, even more preferably 800 μg / g or less, and even more preferably 700 μg / g or less. By setting the content of styrene-based monomer to 3000 μg / g or less, it is possible to suppress the generation of bubbles from the heated surface during heat welding. On the other hand, a content of 100 μg / g or more is preferable because it improves fluidity. The styrene-based monomer contained in the styrene-based resin composition is basically a polymerization residue.

[0081] In this embodiment, the total content of styrene dimers and trimers contained in the styrene-based resin composition is preferably 1.00% by mass or less, more preferably 0.90% by mass or less, even more preferably 0.80% by mass or less, even more preferably 0.70% by mass or less, even more preferably 0.60% by mass or less, even more preferably 0.50% by mass or less, and even more preferably 0.40% by mass or less. By setting the styrene dimer / trimer content to 1.00% by mass or less, it is possible to suppress the generation of bubbles from the heated surface during heat welding. On the other hand, a content of 0.10% by mass or more is preferable because it improves fluidity. The content of styrene dimer / trimer contained in the styrene-based resin composition is basically a by-product generated during polymerization.

[0082] <<Optional added ingredients>> The styrene-based resin composition and acrylic-based resin composition of this embodiment (hereinafter also referred to simply as each resin composition) can also be blended with various optional additive components commonly used in each resin composition to achieve known effects. Examples of optional additive components of this embodiment include higher fatty acid surfactants, lubricating oils, antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, mold release agents, plasticizers, antiblocking agents, antistatic agents, antifogging agents, and colorants. The blending method is not particularly limited, but examples include a method in which the additives are added during polymerization, a method in which the additives are mixed in a blender before melt-kneading after polymerization and then melt-kneaded in an extruder or Banbury mixer, and a method in which a high-concentration masterbatch is prepared and kneaded.

[0083] <Lubricating oil> The lubricating oil in this embodiment is an optional additive component. A resin composition containing the lubricating oil exhibits an effect of improving fluidity and an effect of improving impact resistance (toughness) due to interaction with the optional components, such as the core-shell rubber particles in each resin composition and the impact-resistant styrene-based resin. The lubricating oil used in this embodiment is a general term for oily or waxy substances at room temperature that have a pour point of 110°C or less. The content of lubricating oil in each resin composition of this embodiment is preferably 0.05 to 3.00 mass%, next preferably 0.07 to 2.50 mass%, more preferably 0.10 to 2.30 mass%, even more preferably 0.20 to 1.50 mass%, even more preferably 0.30 to 1.00 mass%, and most preferably 0.40 to 0.70 mass%, based on the total mass of each resin composition (100 mass%). If the content is less than 0.05 mass%, the effect of improving fluidity is not obtained, while if it is more than 3.00 mass%, heat resistance is reduced. In particular, by keeping the content in the range of 0.30 to 1.00 mass%, each resin composition can be obtained with an excellent balance of fluidity, impact resistance, rigidity, and heat resistance.

[0084] Specific examples of lubricating oils used in this embodiment include mineral oils (minerals) derived from crude oil, chemically synthesized oils, natural vegetable oils, etc. Mineral oils include paraffinic and naphthenic oils, chemically synthesized oils include poly-α-olefin oligomers, polybutene oligomers, ethylene propylene copolymer oligomers, fatty acid esters, natural gas modified oils (GTL), alkyl benzene, silicone oil, and polyalkylene glycol oligomers, and natural oils include nut oil, tung oil, shea oil, alfalfa oil, poppy seed oil, pumpkin oil, winter squash oil, millet oil, barley oil, quinoa oil, rye oil, kukui oil, passionflower oil, shea butter, aloe vera oil, sweet almond oil, peach kernel oil, soybean oil, and cashew oil. Examples of suitable lubricating oils include peanut oil, avocado oil, baobab oil, borage oil, broccoli oil, calendula oil, camellia oil, canola oil, carrot oil, safflower oil, flax oil, rapeseed oil, cottonseed oil, coconut oil, pumpkin seed oil, wheat germ oil, jojoba oil, lily oil, macadamia oil, corn oil, medfoam oil, monoi oil, hazelnut oil, apricot kernel oil, walnut oil, olive oil, evening primrose oil, palm oil, blackcurrant seed oil, kiwi seed oil, grapeseed oil, pistachio oil, musk rose oil, sesame oil, soybean oil, sunflower oil, castor oil, and watermelon oil. Chemically modified versions of the above lubricating oils may also be used. For example, lubricating oils that have had the double bond content adjusted by hydrogenation (hydrogen addition), or that have been epoxidized, aminated, or mercapto-modified may be used as needed. Liquid paraffin and silicone oil are preferred because they are industrially available, with silicone oil being particularly preferred from the viewpoint of improving impact resistance.

[0085] In this embodiment, the kinematic viscosity of the lubricating oil is 1000 mm at 25°C. 2 / s or less, and 20 to 1000 mm 2 / s is more preferable, and 50 to 500 mm 2 / s, and more preferably 70 to 300 mm 2 Even more preferably, it is / s.

[0086] The pour point of the lubricating oil in this embodiment is 110°C or lower, preferably 100°C or lower, more preferably 90°C or lower, even more preferably 80°C or lower, still more preferably 50°C or lower, even more preferably 30°C or lower, even more preferably 10°C or lower, even more preferably 0°C or lower, even more preferably -20°C or lower, even more preferably -30°C or lower, and particularly preferably -40°C or lower. If the pour point of the lubricating oil exceeds 100°C, the lubricating oil is difficult to disperse in each resin composition, making addition or mixing operations difficult. In particular, by using a lubricating oil with a pour point of -30°C or lower, a high impact resistance improvement effect can be obtained.

[0087] A lubricating oil with a low content of low-boiling components is effective in avoiding problems with volatile matter during extrusion molding. It is preferable that the 5% distillation temperature is 400°C or higher as calculated at atmospheric pressure from the vacuum distillation method or gas chromatography method according to JIS K2254.

[0088] The method for adding the lubricating oil is not particularly limited, and examples thereof include a method of adding the lubricating oil during the polymerization step, and a method of kneading the lubricating oil using a known kneader such as a single-screw extruder, a twin-screw extruder, or a Banbury mixer. The lubricating oil and its identity in this embodiment can be easily identified by those skilled in the art using common methods. For example, pyrolysis GC-MS, liquid chromatography (LC), 1 H-NMR or 13 Identification, quantification, and molecular weight measurement can be performed using various analytical devices such as C-NMR.

[0089] <Monohydric alcohols with 10 or more carbon atoms> In this embodiment, the monohydric alcohol having 10 or more carbon atoms (hereinafter simply referred to as alcohol) is an optional additive component that suppresses gelation of the copolymer (S) during molding, contributing to the improvement of the appearance of each resin composition and molded articles made from each resin composition. The content of the monohydric alcohol having 10 or more carbon atoms is 0.01 to 1.0 mass%, preferably 0.03 to 0.8 mass%, more preferably 0.05 to 0.6 mass%, and even more preferably 0.07 to 0.5 mass%, relative to the total amount (100 mass%) of each resin composition. By setting the content of the monohydric alcohol having 10 or more carbon atoms to 0.01 mass% or more, gelation of the copolymer (S) during molding processing can be suppressed, while by setting it to 1.0 mass% or less, a decrease in heat resistance and the generation of odor can be suppressed. By setting the content of the monohydric alcohol having 10 or more carbon atoms to 0.07 to 0.5 mass%, a sufficient gel suppression effect can be obtained without particularly decreasing heat resistance.

[0090] The monohydric alcohol having 10 or more carbon atoms is an alcohol having 10 or more carbon atoms and one hydroxyl group, and may contain a heteroatom such as oxygen or nitrogen in the carbon chain constituting the alcohol, and may contain a bond other than a single bond, such as a double bond, a triple bond, an ester bond, or an amide bond in the carbon chain. The number of carbon atoms is preferably 16 or more, more preferably 17 or more, and even more preferably 18 to 50. The monohydric alcohol having 10 or more carbon atoms may be contained in a styrene-based resin composition or a molded article made of a styrene-based resin composition. Therefore, by having a monohydric alcohol having 10 or more carbon atoms present (or added) in a polymerization solution used in polymerizing the copolymer (S), the monohydric alcohol may remain in the resin composition as a final product, or may be added when kneading the copolymer (S) with other additives and mixed in an extruder.

[0091] In this embodiment, the boiling point of the monohydric alcohol having 10 or more carbon atoms is preferably 260° C. or higher, more preferably 270° C. or higher, and even more preferably 290° C. or higher. If the boiling point of the alcohol is lower than 260° C., it becomes highly volatile and tends to generate an unpleasant odor during molding, etc.

[0092] The monohydric alcohol having 10 or more carbon atoms is not particularly limited, but examples thereof include 1-hexadecanol, isohexadecanol, 1-octadecanol (stearyl alcohol), 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-1-octanol, isooctadecanol, 1-isoisoeicosanol, 8-methyl-2-(4-methylhexyl)-1-decanol, 2-heptyl-1-undecanol, 2-heptyl-4-methyl-1-decanol, 2-(1,5-dimethylhexyl)-(5,9-dimethyl)-1-decanol, and polyoxyethylene alkyl ethers.

[0093] The polyoxyethylene alkyl ethers are preferably compounds represented by the following general formula (2): [ka] (In the above general formula (2), R is an alkyl group having 12 to 20 carbon atoms, and X represents the average number of ethylene oxides added and is an integer of 1 to 15.) Specific examples of preferred alcohols include "Fine Oxocol 180" manufactured by Nissan Chemical Industries, Ltd., and "Emulgen 109P" and "Kalcol 8098" manufactured by Kao Corporation.

[0094] <Antioxidants> The antioxidant in this embodiment is an optional additive component and is added to each resin composition as needed for purposes such as long-term stability and molding stability. Examples of antioxidants include hindered phenolic antioxidants such as octadecyl-3-(3,5-tert-butyl-4-hydroxyphenyl)propionate and 4,6-bis(octylthiomethyl)-o-cresol (product Irganox 1076), and phosphorus-based antioxidants such as tris(2,4-di-tert-butylphenyl)phosphite (product Irgafos 176). These antioxidants may be used alone or in combination of two or more. In particular, combining a phenolic antioxidant as a primary antioxidant with a phosphorus-based antioxidant as a secondary antioxidant provides an excellent synergistic effect. The amount of antioxidant added is preferably 0.001 to 3.0 mass% relative to the total mass of each resin composition (100 mass%), more preferably 0.010 to 2.0 mass%, even more preferably 0.050 to 1.0 mass%, still more preferably 0.080 to 0.8 mass%, and even more preferably 0.1 to 0.6 mass%.

[0095] <Release agent> The release agent in this embodiment is an optional additive component, and it is preferable that each resin composition contains a release agent, particularly when the resin composition is subjected to injection molding. The release agent may be contained in the form of an internal lubricant that is kneaded when preparing each resin composition, or in the form of an external lubricant that is dry-blended with each resin composition immediately after granulation, or in a combination of the two.

[0096] The content of the release agent in this embodiment is preferably 0.001 to 2.0% by mass relative to the total amount (100% by mass) of each resin composition, and the upper limit is 1.8% by mass or less, 1.7% by mass or less, 1.6% by mass or less, 1.5% by mass or less, 1.4% by mass or less, 1.3% by mass or less, 1.2% by mass or less, 1.1% by mass or less, 1.0% by mass or less, 0.9% by mass or less, 0.8% by mass or less, 0.7% by mass or less. The lower limit is preferably 0.003% by mass or more, 0.005% by mass or more, 0.007% by mass or more, 0.009% by mass or more, 0.012% by mass or more, 0.031% by mass or more, 0.066% by mass or more, 0.090% by mass or more, 0.11% by mass or more, 0.16% by mass or more, 0.21% by mass or more, 0.26% by mass or more, and 0.31% by mass or more. By setting the content in the range of 0.001 to 2.0% by mass, each resin composition can be obtained with excellent release properties, and by setting the content in the range of 0.01 to 0.8% by mass in particular, each resin composition can be obtained with an excellent balance between release properties and heat resistance.

[0097] When each resin composition of the present embodiment contains a release agent as an internal lubricant, the content of the internal lubricant is preferably 0.05 to 2.0 mass%, more preferably 0.10 to 1.5 mass%, more preferably 0.13 to 1.0 mass%, and even more preferably 0.17 to 0.8 mass%, relative to the total amount (100 mass%) of each resin composition. In particular, by setting the content in the range of 0.13 to 1.0 mass%, excessive bleeding out can be suppressed and each resin composition with excellent release properties can be obtained.

[0098] When each resin composition of the present embodiment contains a mold release agent as an external lubricant, the content of the mold release agent as the external lubricant is preferably in the range of 0.005 to 0.5 mass%, more preferably 0.007 to 0.2 mass%, and even more preferably 0.008 to 0.1 mass%, relative to the total amount (100 mass%) of each resin composition. In particular, by setting the content in the range of 0.008 to 0.1 mass%, mold contamination can be suppressed and each resin composition with excellent mold releasability can be obtained.

[0099] Examples of the release agent of the present embodiment include stearyl alcohol, stearic acid, zinc stearate, calcium stearate, glycerin, glycerol mosstearate, ethylene bisstearic acid amide, stearic acid amide, oleic acid amide, erucic acid amide, glycerin, glycerin monostearate, glycerin distearate, glycerin tristearate and other glycerin esters, pentaerythritol stearate, etc. From the viewpoint of compatibility with styrene-based resins, ethylene bisstearic acid amide, stearyl alcohol, stearic acid, zinc stearate, and calcium stearate are preferred.

[0100] <Light stabilizer> The light stabilizer in this embodiment is an optional additive component, and is preferably added as needed when each resin composition is used in applications where light degradation, such as outdoors, is a concern. Light stabilizers do not themselves have UV absorption capabilities, but they capture and neutralize photoradicals generated by the styrene-based resin composition when it absorbs UV light, thereby preventing radical-induced degradation and discoloration of each resin composition. Due to this mechanism, they are expected to function as thermal radical scavengers and can therefore also function as heat stabilizers. Preferred light stabilizers are hindered amine compounds, including secondary amine, tertiary amine, and NOR-type hindered amine compounds. Light stabilizers can be used alone or in combination of two or more types. Using a UV absorber, as described below, in combination can achieve even greater light resistance. In other words, they can suppress discoloration and strength reduction after exposure of the styrene-based resin composition or a molded article thereof during long-term outdoor use. Light stabilizers function mainly on the surface of resins where photoradical generation is common, so if you want to maximize their effectiveness, low-molecular-weight types are preferable. However, if you want to prevent mold contamination due to excessive bleed-out or if you need a longer-term stabilizing effect, you will need to adjust the molecular weight appropriately or consider using both low-molecular-weight and high-molecular-weight types in combination.

[0101] The content of the light stabilizer is preferably 0.001 to 2.0% by mass relative to the total amount of each resin composition, with the upper limit being preferably 1.8% by mass or less, 1.6% by mass or less, 1.4% by mass or less, 1.2% by mass or less, 1.0% by mass or less, 0.8% by mass or less, and 0.7% by mass or less, and the lower limit being preferably 0.005% by mass or more, 0.010% by mass or more, 0.021% by mass or more, 0.051% by mass or more, 0.061% by mass or more, 0.071% by mass or more, 0.079% by mass or more, 0.089% by mass or more, 0.12% by mass or more, and 0.17% by mass or more, in that order. The content of the light stabilizer can be selected from any combination of the above upper and lower limits.

[0102] The light stabilizer is preferably a hindered amine compound. Specific examples of the hindered amine compound include bis(1,2,2,6-pentamethyl-4-piperidyl)sebacate, bis(1-undecaneoxy-2,2,6,6-tetramethylpiperidin-4-yl)carbonate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexane-1,6-diamine, and butyl(3,5-di-t-butyl-4 -hydroxybenzyl)malonate bis(1,2,2,6,6-pentamethyl-4-piperidyl), and specific product names include ADK STAB LA-52, ADK STAB LA-57, ADK STAB LA-63P, ADK STAB LA-68, ADK STAB LA-72, ADK STAB LA-77Y, ADK STAB LA-77G, and ADK STAB LA-81 manufactured by ADEKA Corporation, JF-90G and JF-95 manufactured by Johoku Chemical Co., Ltd., and Chimassorb 2020FDL, Chimassorb 944FDL, and Tinuvn 622SF manufactured by BASF Japan Ltd.

[0103] <UV absorber> The UV absorber in this embodiment is an optional additive component and is preferably added as needed when using each resin composition in applications where photodegradation is a concern, such as outdoors. The UV absorber absorbs UV light absorbed by each resin composition on behalf of the resin composition and converts it into heat or chemical energy, thereby suppressing the generation of photoradicals due to UV absorption by each resin composition and suppressing resin degradation and coloration. The UV absorber is preferably a compound having two or more aromatic rings linked via a linking group containing an atom with an unpaired electron (oxygen atom, nitrogen atom, sulfur atom, phosphorus atom, etc.), with one or more aromatic rings having a phenolic hydroxyl group. Such compounds may have a chemical structure that absorbs light, becomes excited, and then converts it into chemical energy. Examples of UV absorbers include benzotriazole-based compounds, triazine-based compounds, benzophenone-based compounds, benzoate-based compounds, cyanoacrylate-based compounds, oxalic acid anilide-based compounds, malonic acid ester-based compounds, formamidine-based compounds, and salicylate-based compounds. These ultraviolet absorbers can be used alone or in combination of two or more. By using the light stabilizer and ultraviolet absorber in combination, a higher light resistance effect can be achieved, in other words, coloration and strength reduction of each resin composition after exposure to light can be suppressed.

[0104] The content of the ultraviolet absorber in this embodiment is preferably 0.001 to 2.0% by mass relative to the total amount of each resin composition, with upper limits of 1.8% by mass or less, 1.6% by mass or less, 1.4% by mass or less, 1.2% by mass or less, 1.0% by mass or less, 0.8% by mass or less, and 0.7% by mass or less being preferred in this order, and lower limits of 0.005% by mass or more, 0.010% by mass or more, 0.021% by mass or more, 0.051% by mass or more, 0.061% by mass or more, 0.071% by mass or more, 0.079% by mass or more, 0.089% by mass or more, 0.12% by mass or more, and 0.17% by mass or more being preferred in this order. The content of the ultraviolet absorber can be selected from any combination of the above upper and lower limits.

[0105] Examples of the benzotriazole-based compound include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol, 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 6-(2-benzotriazolyl)-4-tert-octyl-6'-tert-butyl-4'-methyl-2,2'-methylenebisphenol]2-(2'-hydroxy-3'-tert- butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, and the like. Specific product names include ADK STAB LA-32, ADK STAB LA-36, and ADK STAB LA-36RG manufactured by ADEKA CORPORATION, JF-77, JF-79, JF-80, JF-83, JF-832, and JAST-500 manufactured by Johoku Chemical Co., Ltd., and Tinuvin P, Tinuvin 234, Tinuvin 234FF, Tinuvin 326, Tinuvin 329, and Tinuvin 360 manufactured by BAST Japan.

[0106] Examples of the triazine compounds include 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]phenol, 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine, N,N',N''-tri(m-tolyl)-1,3,5-triazine-2,4,6-triamine, 2,4,6-tris(4-butoxy-2-hydroxyphenyl)-1,3,5-triazine, 2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-n-octyloxyphenyl)-1,3,5-triazine, and ethylhexanoyloxyphenyl. Examples include siltriazine, 2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2,4,6-tris(2,4-dihydroxyphenyl)-1,3,5-triazine, bemotodinol, 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine, and 2-(2,4-dihydroxyphenyl)-4,6-diphenyl-1,3,5-triazine. Specific product names include Adeka STAB LA-46 and Adeka STAB LA-F70 manufactured by ADEKA Corporation, and Tinuvin 1577ED and Tinuvin 1600 manufactured by BAST Japan.

[0107] Examples of the benzophenone compounds include 2-hydroxy-4-(octyloxy)benzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,4-dihydroxybenzophenone, and 2,2',4,4'-tetrahydroxybenzophenone. Specific product names include Adekastab 1413 manufactured by ADEKA Corporation, and Chimassorb 81 and Chimassorb 81 FL manufactured by BAST Japan.

[0108] <Coloring agent> The colorant in this embodiment is an optional additive component and is used when it is necessary to color each resin composition. In particular, when each resin composition is applied to an in-vehicle related component, it is often colored black. Coloring it black can impart a preferable appearance for in-vehicle application and some resistance to heat and light. The colorant is not particularly limited, but carbon black, titanium oxide, and organic dyes can be used. Examples of carbon black include those produced by the furnace method (furnace black), channel method (channel black), acetylene method (acetylene black), and thermal method (thermal black).

[0109] When each resin composition is colored black with carbon black, the carbon black content in each resin composition is preferably 0.05 to 5.0% by mass relative to the total resin composition (100% by mass). If the carbon black content is 0.05% by mass or less, the desired blackness will not be achieved and the resin will turn grayish. If the carbon black content is 5.0% by mass or more, the blackness will not change. From the viewpoints of cost and mechanical strength, the carbon black content is preferably 5.0% by mass or less. The method of adding the colorant is not particularly limited. The colorant may be added after polymerization, directly blended during kneading, or added during kneading using a high-concentration masterbatch.

[0110] <Colorant masterbatch> Hereinafter, a method of adding a colorant, which is an optional additive component in this embodiment, using a masterbatch will be described. The base resin of the masterbatch is preferably the copolymer (S) or the copolymer (A). The content of the base resin in the masterbatch is preferably 30 to 70 mass %, more preferably 40 to 60 mass %, relative to the total amount of the masterbatch. By setting the content to 30 mass % or more, the viscoelasticity of the resin can be imparted, making it easier to handle. By setting the content to 70 mass % or less, it becomes easier to allow the desired amount of colorant to be present in each resin composition, and it is also advantageous in terms of cost. For the same reasons as above, the content of the colorant in the masterbatch is preferably 30 to 70 mass %, more preferably 40 to 60 mass %, relative to the total amount of the masterbatch.

[0111] When the colorant is a powder pigment such as carbon black, it is preferable to include a dispersant in addition to the base resin and colorant when preparing the masterbatch. Commonly used dispersants can be used as the dispersant, including higher fatty acid metal salts such as stearic acid, zinc stearate, magnesium stearate, and calcium stearate, higher fatty acid amides such as ethylene bisstearamide, polyethylene wax, and modified polyethylene wax. Polyethylene wax is preferred from the viewpoint of reactivity with the copolymer (S). The content of the dispersant is preferably 2 to 20% by mass, more preferably 3 to 17% by mass, based on the total amount of the masterbatch. Although depending on the amount of the colorant, a content of 2% by mass or more allows the colorant to be dispersed, and a content of 20% by mass or less can prevent a decrease in the heat resistance of each resin composition.

[0112] The masterbatch can be produced by blending a colorant and, if necessary, a dispersant into a base resin, and then adjusting the blend using a kneading extruder or kneader. The kneading temperature is preferably 200 to 280°C, and more preferably 220 to 260°C.

[0113] "Automotive rear lamp housing" The heterogeneous resin composite member of the present disclosure can be used as an automotive lamp, preferably an automotive lamp housing, and particularly an automotive rear lamp housing. The configuration of an automotive rear lamp housing will be described below with reference to Fig. 3. Fig. 3 shows a cross-sectional view of an example of an automotive lamp having an automotive rear lamp housing 2 and a cover 3 joined to the automotive rear lamp housing 2 by hot plate welding. As shown in Fig. 3, the vehicle lamp 100 has an in-vehicle rear lamp housing 2 and a cover 3, and the cover 3 is joined to the in-vehicle rear lamp housing 2 by hot plate welding. As described above, the in-vehicle lamp 100 is joined by joining the cover 3 to the in-vehicle rear lamp housing 2 by hot plate welding, and then crimping the cover 3 to the in-vehicle rear lamp housing 2 during the hot plate welding. Therefore, in the example of the in-vehicle lamp 1 shown in Fig. 3, the crimping direction S is the up-down direction.

[0114] The vehicle-mounted rear lamp housing 2 is a styrene-based resin member formed from, for example, the above-mentioned styrene-based resin composition. When the styrene-based resin member is used for the vehicle-mounted rear lamp housing 2, the vehicle-mounted rear lamp housing 2 has an internal space. The vehicle-mounted rear lamp housing 2 also has a concave main body 4 having an opening, an annular edge 5 that protrudes outward from the upper end of the main body 4, and an annular joining protrusion 6 that protrudes outward from the edge 5. The upper surface of the joining protrusion 6 is formed as a welding surface 6a to be welded to the cover 3.

[0115] The cover 3 is, for example, an acrylic resin member formed from the above-mentioned acrylic resin composition. When an acrylic resin member is used for the cover 3, the cover 3 is transparent, and an outer surface 3a is integrally formed with an outer surface portion 7 on the outside of the vehicle and welding legs 8 protruding from a portion of the inner surface 7a of the outer surface portion 7 near the outer periphery. The cover 3 is joined to the vehicle-mounted rear lamp housing 2 in a state where it covers the internal space of the vehicle-mounted rear lamp housing 2. The outer surface portion 7 is curved so as to convex outward (or toward the opposite side of the vehicle-mounted rear lamp housing 2) according to the shape of the vehicle body, etc., and is formed into a curved shape. The portion of the outer surface portion 7 outside the welded leg portions 8 is provided as a shielding portion 9. The portion of the outer surface portion 7 inside the shielding portion 9, which is the portion from which the welded leg portions 8 protrude, is provided as a protrusion-forming portion 10, and the portion inside the protrusion-forming portion 10, i.e., the portion other than the shielding portion 9 and the protrusion-forming portion 10, is provided as a light-transmitting portion T.

[0116] The weld leg portion 8 is composed of a continuous portion 12 that continues from the outer surface portion 7 and a bent portion 13 that is bent relative to the continuous portion 12. Furthermore, the tip surface of the bent portion 13 of the weld leg portion 8 is formed as a joint surface 8a, and the tip portion of the bent portion 13 including the joint surface 8a is provided as a joint portion 8b. Furthermore, the boundary portion of the weld leg portion 8 between the continuous portion 12 and the bent portion 13 is formed as a bent end portion 8c. The continuous portion 12 is attached so as to protrude, for example, in a direction substantially perpendicular to the extending direction of the shielding portion 9 and the protrusion forming portion 10. The bent portion 13 is bent relative to the continuous portion 12 toward the outer periphery of the outer surface portion 7, i.e., toward the shielding portion 9. The connecting direction of the bent portion 13 is the direction connecting the joint portion 8b and the bent end portion 8c. The knotting direction of the bent portion 13 is aligned with the crimping direction S. However, it is sufficient that the knotting direction is aligned with the crimping direction S at an angle equal to or smaller than a certain value.

[0117] The steps of the method for joining the cover 3 to the vehicle-mounted rear lamp housing 2 by hot plate welding will be briefly described below. When the cover 3 is joined to the vehicle rear lamp housing 2 by hot plate welding, the vehicle rear lamp housing 2 and the cover 3 are held by a first jig and a second jig, respectively, and the cover 3 is held in a position spaced apart from the vehicle rear lamp housing 2. Next, with the vehicle-mounted rear lamp housing 2 and the cover 3 held by the first jig and the second jig, respectively, a hot plate is positioned between the vehicle-mounted rear lamp housing 2 and the cover 3, and the joining protrusion 6 of the vehicle-mounted rear lamp housing 2 and the welding leg 8 of the cover 3 are heated by the hot plate. The heating by the hot plate brings the upper end including the welding surface 6a of the joining protrusion 6 and the joining portion 8b of the welding leg 8 into a meltable state.

[0118] Then, the hot plate is removed from between the vehicle-mounted rear lamp housing 2 and the cover 3, and the second jig is lowered to press the cover 3 against the vehicle-mounted rear lamp housing 2 in the crimping direction S, so that the joining surfaces 8a of the welding legs 8 are crimped against the welding surfaces 6a of the joining protrusions 6. At this time, the upper ends of the joining protrusions 6, including the welding surfaces 6a, and the joining portions 8b of the welding legs 8 are in a meltable state, so that the upper ends of the joining protrusions 6 and the joining portions 8b of the welding legs 8 are melted, and the cover 3 is joined to the vehicle-mounted rear lamp housing 2.

[0119] Thereafter, the vehicle-mounted rear lamp housing 2 and the cover 3 are removed from the first jig and the second jig, respectively, and the joining operation of the cover 3 to the vehicle-mounted rear lamp housing 2 by hot plate welding is completed.

[0120] Furthermore, the cover 3 is joined to the vehicle rear lamp housing 2, whereby the vehicle rear lamp housing 2 and the cover 3 form a lamp outer casing 1. A lamp unit (not shown) having required components such as a light source and a reflector is disposed in the internal space of the lamp outer casing 1, thereby forming the vehicle lamp 100. In the vehicle lamp 100, light emitted from the light source is reflected by, for example, a reflector, transmitted through the light transmitting portion T of the cover 3, and irradiated toward the outside. [Example]

[0121] The present invention will now be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. The resins, resin compositions, and molded articles used in the examples and comparative examples were analyzed and evaluated as follows.

[0122] [Evaluation of properties of each resin and resin composition] (1) Measurement of the content of each monomer unit The content of each monomer unit contained in each resin and resin composition prepared in the Examples and Comparative Examples was measured by pyrolysis GC / MS under the following conditions. <<Sample Preparation>> 20 μg of the resin or composition prepared in the examples and comparative examples was weighed out into a sample cup using a precision balance. <<Measurement conditions>> <Pyrolysis unit> Equipment: Frontier Labs PY-3030D Furnace temperature: 600℃ <GC / MSユニット> Equipment: Shimadzu GCMS-GP2020NX Column: Ultra Alloy-5 (Length 30m, film thickness 0.25μm, diameter 0.250mmφ) Column temperature: Maintain at 50°C for 5 minutes, then increase at 10°C / min. The temperature was increased at 7°C / min and held at 300°C for 10 minutes. Inlet temperature: 300℃ Detector temperature: 300℃ Split ratio: 1 / 300 Carrier gas: Helium Detection device: Mass spectrometer (MSD) Detection conditions: Scan mode or SIM mode (when unnecessary peaks and peaks to be detected overlap) When detecting each monomer peak, in order to avoid saturation of peak intensity or overlapping of peaks to be detected, the amount of sample may be appropriately adjusted, and detection conditions such as the column to be used and the rate of temperature rise may be appropriately adjusted.

[0123] (2) Measurement of average molecular weight The average molecular weights (Mn, Mw, Mz) of each resin and resin composition produced in the examples and comparative examples were measured as molecular weights converted into standard polystyrene by gel permeation chromatography (GPC) using a calibration curve method using standard polystyrene under the following conditions. Measuring equipment: Tosoh HLC-8220 Separation column: Two TSK gel Super HZM-H (inner diameter 4.6 mm) manufactured by Tosoh Corporation connected in series Guard column: Tosoh TSK guard column Super HZ-H Measurement solvent: tetrahydrofuran (THF) Sample concentration: 5 mg of the measurement sample was dissolved in 10 mL of solvent and filtered through a 0.45 μm filter. Injection volume: 10μL Measurement temperature: 40℃ Flow rate: 0.35mL / min Detector: differential refractometer The calibration curve was created using 11 types of TSK standard polystyrene (F-850, F-450, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000) manufactured by Tosoh Corporation. The calibration curve was created using a linear approximation equation. If any THF-insoluble matter was present in the composition, it was removed using a 0.2-0.5 μm membrane filter before measurement.

[0124] (3) Measurement of Vicat softening temperature (℃) Measurements were performed in accordance with ISO306 under test conditions of a load of 5 kg and a temperature rise rate of 50°C / hour.

[0125] (4) Measurement of lightness (L*) (-) The lightness (L*) of the test specimen was measured in accordance with JIS Z8722. A 2 mm thick plate manufactured by injection molding was used as the test specimen. A spectrophotometer (Konica Minolta CM-2002) was used to measure the lightness (L*). The measurement was performed in SCI mode (specular reflection included). The n3 average value was used as the measured value.

[0126] (5) Total light transmittance and yellowness index (YI) measurement of 2mm plate Each resin composition was injection molded into a 2 mm plate, and after conditioning for 24 hours or more in a thermostatic chamber at 23°C and 50% humidity, the total light transmittance was measured in accordance with JIS K7375 and the yellowness index YI in accordance with JIS K7373 using a color difference turbidity meter (COH-300A) manufactured by Nippon Denshoku Industries Co., Ltd. The n3 average was used as the value.

[0127] (6) Hansen Solubility Parameter (HSP) value [(J / cm 3 ) 1 / 2 Measurement of The HSP values ​​of the acrylic resin composition and the styrene resin composition were calculated by the following procedure. A resin composition sample was placed in a glass vial, an organic solvent with a known HSP value was added, and the mixture was shaken under the following conditions. The solubility was evaluated visually and by touch according to the following criteria. Test conditions Test period: 24±1 hours Test temperature: 23±2℃ Solvent amount: 3mL Resin (composition) amount: 30±10mg Organic solvents: 24 types listed below Acetone, acetonitrile, 1-butanol, butyl acetate, chloroform, cyclohexane, diethylene glycol, N,N-dimethylformamide, dimethyl sulfoxide, 1,4-dioxane, ethanol, methanol, methyl isobutyl ketone, N-methyl-2-pyrrolidone, propylene carbonate, propylene glycol-1-monomethyl ether-2-acetate, tetrachloroethylene, tetrahydrofuran, toluene, 4-butyrolactone, m-cresol, diethyl ether, 2-ethyl-1-hexanol, methyl ethyl ketone Evaluation criteria S: Completely dissolved A: Although it did not dissolve completely, it did not retain its original shape and turbidity or sedimentation occurred. B: Largely swollen C: No visible change was observed, but the surface was softened when touched with a spatula D: No change Next, a three-dimensional plot (δ d ,δ p ,δ h The solubility evaluation results were reflected on the HSP value (δ d ,δ p ,δ h ) was calculated using the Advanced Fitting function of Hansen Solubility Parameters in Practice (HSPiP) version 5.3.06.

[0128] (7) Heat resistance evaluation of composite materials made from different resins The heterogeneous resin composite members produced in the examples and comparative examples were placed in an oven set at 115°C with the styrene resin member side facing downwards (in contact with the oven bottom) and the acrylic resin member side facing upwards (not in contact with the oven bottom or walls). After 15 minutes, the changes were visually evaluated according to the following criteria to evaluate heat resistance. A: No dimensional change of the component is observed B: Dimensional changes are observed in the components, but no changes are observed in the joints. C: Dimensional changes in the components are observed, and the joints peel off.

[0129] (8) Evaluation of joint strength of composite materials made of different resins The composite members of different resins prepared in the examples and comparative examples were dropped from a height of 80 cm onto a smooth stainless steel plate with the joint interface between the styrene-based resin member and the acrylic-based resin member perpendicular to the ground. The above test was carried out on 10 composite members of different resins, and the mechanical strength was evaluated according to the following criteria. S: The number of samples in which peeling occurred at the joint was 0 A: The number of samples in which peeling occurred at the joint was 2 or less. B: The number of samples where peeling occurred at the joint was 3 to 6 or less. C: The number of samples where peeling occurred at the joint was 7 or more.

[0130] (9) Evaluation of mechanical strength of composite materials made of different resins The dissimilar resin composite members produced in the examples and comparative examples were dropped onto a smooth stainless steel plate from a height of 120 cm with the styrene resin member side facing downwards and the acrylic resin member side facing upwards. The above evaluation was carried out on 10 dissimilar resin composite members, and the mechanical strength was evaluated according to the following criteria. S: Number of broken samples is 0 A: The number of broken samples is 3 or less. B: The number of broken samples is 4 to 6. C: The number of broken samples is 7 or more

[0131] (10) Evaluation of assembly cycle performance of composite materials made of different resins The method for evaluating the assembly cycle property of the composite member made of different resins will be described in detail in Example 1 below. (18) Sample production of composite materials made from different resins Samples were prepared by joining styrene resin members (S1) to (S8) made of the following styrene resin compositions with acrylic resin members made of the following acrylic resin compositions (A1) to (A2). Specifically, using an EC60N manufactured by Toshiba Machine Co., Ltd., 4 mm dumbbell-shaped styrene resin members and acrylic resin members of Type A (see FIG. 4, 10A) were molded under the following conditions. Pellets drying: 80°C for 2 hours or more Measurement: 63mm Injection time: 20 seconds Holding pressure switching: Short shot point of 10mm or less Holding pressure: Maximum injection pressure when holding pressure is 0 MPa during short shots x 1.0 MPa Pressure retention time: 10 seconds Cylinder temperature: 230-250-230-210℃ from nozzle side to hopper side Screw rotation speed: 100 times / min Cushion: 4.5~5.5mm Mold temperature: 60℃ Cooling time: 25 seconds Each dumbbell piece (10A in FIG. 4) was cut at a position 7.6 cm from the gate side to prepare a test piece (see 10B in FIG. 4). Next, the side of the test piece opposite the ejector pin of the styrene-based resin composition prepared in the Examples and Comparative Examples and the side of the test piece opposite the ejector pin of the acrylic resin composition of Synthesis Examples 1 and 2 were overlapped at a position 3 cm from the cut surface and fixed with heat-resistant Teflon tape to prepare a test piece. The test piece (10B) was placed in an oven set to a temperature of 150°C, and a 0.5 kg dumbbell preheated in the oven was placed on the adhesive surface of the test piece (10B) between the styrene resin composition and the acrylic resin material, and the test piece was left standing in the oven for 10 minutes. To prevent thermal deformation of the dumbbell, the dumbbell was fixed with a metal plate preheated in the oven. The test piece (10B) was removed from the oven and allowed to cool in air for 5 minutes, yielding a test piece (10C) in which the styrene resin composition and the acrylic resin material were heat-welded. (See 10C in Figure 4 for the obtained test piece.)

[0132] [Example of manufacturing a composite material made from different resins] Specific methods for producing each of the composite members made of different resins will be described below.

[0133] <<Optional additives used in the examples>> <Lubricating oil> In the examples of this specification, when silicone oil was used as the lubricating oil, PP-17 (product name), polydimethylsiloxane oil manufactured by GE Toshiba Silicones, was used.

[0134] <Core-shell rubber particles> In the examples herein, when core-shell rubber particles were used, Mitsubishi Chemical Corporation's Metablen E-875A (product name) "shell: polymethyl methacrylate, core: polybutadiene" was used.

[0135] <High impact polystyrene> In the examples herein, when high impact polystyrene was used, a styrene-based resin composition (S8) was used.

[0136] <Monohydric alcohols with 10 or more carbon atoms> In the examples herein, when a monohydric alcohol having 10 or more carbon atoms was used, Fine Oxocol 180 (product name) manufactured by Nissan Chemical Industries, Ltd. (compound name: 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-1-octanol) was used.

[0137] <Release agent (internal lubricant)> In the examples of the present specification, Kalcol 8098 (product name) manufactured by Kao Corporation (compound name: stearyl alcohol) was used as the mold release agent (internal lubricant).

[0138] <Coloring agent> A carbon black masterbatch for coloring a styrene-based resin composition black was prepared according to the following procedure. -Preparation of black masterbatch- 2.8 kg of composition (S3) described below, 2.8 kg of carbon black, and 0.5 kg of polyethylene wax were dry blended, kneaded, extruded, and pelletized to obtain black pellets, a black masterbatch having composition (A1) as a base resin.

[0139] <<Acrylic resin composition used in the examples>> Table 1 below shows the formulations of the acrylic resin compositions used in the examples.

[0140] [Table 1]

[0141] <<Styrene-based resin composition used in the examples>> Table 2 below shows the compositions of the styrene-based resin compositions used in the examples.

[0142] [Table 2]

[0143] <Preparation of styrene-based resin composition by compounding> The styrene resin compositions (SC1) to (SC3) were prepared by kneading the ingredients in the blending ratios shown in Table 3 below using a twin-screw (same direction) extruder. The cylinder temperature of the extruder was 180 to 230°C, and the resin temperature was 240 to 270°C.

[0144] [Table 3]

[0145] [Example 1] The acrylic resin composition (A1) in Table 1 was injection molded into a cover-shaped acrylic resin member (A1*) with a 30 cm × 30 cm outer periphery and a 2 cm smooth adhesive surface (acrylic resin member 33 in Figure 1, W1 = 30 cm, D1 = 30 cm). The styrene resin composition (S1) in Table 2 was injection molded into a 2 cm thick housing-shaped styrene resin member (S1*) with an opening and a 2 cm adhesive surface on one face of a cube with three 26 cm sides (styrene resin member 22 in Figure 1, W2 = 26 cm, D2 = 26 cm, H2 = 26 cm, w0 = 2 cm). Next, a cover-shaped acrylic resin member (A1*) and a housing-shaped styrene-based resin member (S1*) were placed across a hot plate heated to 400°C. Each member was placed within 0.5 cm of the hot plate, with their adhesive surfaces facing the hot plate. The heating time (T) was 40 seconds. The hot plate was then removed, and the adhesive surfaces of the acrylic resin member (A1*) and the styrene-based resin member (S1*) were pressed together. After air cooling for 3 minutes, a heterogeneous resin composite member [1] was obtained (heterogeneous resin composite member 11 in Figure 2, W3 = 30 cm, D3 = 30 cm, H3 = 26 cm). The evaluation results of the resulting heterogeneous resin composite member [1] and the calculated parameters for the combination of the acrylic resin member (A1*) and the styrene-based resin member (S1*) are shown in Table 4. On the other hand, to evaluate the assembly cycle property, the heating time (T) was increased from 10 seconds to 30 seconds in 2-second increments to create three heterogeneous resin composite members [1'] for each heating time. The obtained heterogeneous resin composite member [1'] was placed on a smooth surface with the acrylic resin member (A1*) facing upwards, and while fixed so as not to move, a palm was placed on the surface of the acrylic resin member (A1*). When a shear stress was applied horizontally to the surface of the acrylic resin member (A1*), the heating time (T) at which all three pieces did not peel off was determined as the minimum heating time (T min The assembly cycle properties were evaluated based on the following criteria. The results of the assembly cycle properties evaluation are shown in Table 4. S: Minimum heating time (T min ) in 18 seconds or less A: Minimum heating time (T min) is over 18 seconds and under 24 seconds B: Minimum heating time (T min ) is over 24 seconds and less than 30 seconds C: Minimum heating time (T min ) for over 30 seconds

[0146] [Examples 2 to 10] Different resin composite members [2] to

[10] were produced and evaluated in the same manner as in Example 1, except that the combinations of the acrylic resin compositions and styrene resin compositions used in the members were changed as shown in Table 4. Table 4 shows the evaluation results of the obtained different resin composite members [2] to

[10] and the calculated values ​​of each parameter based on the combination of each resin member.

[0147] [Comparative Examples 1 to 3] Each part was molded using a combination of the acrylic resin composition (A1) and a styrene resin composition (S4) mainly composed of a styrene homopolymer, and heterogeneous resin composite parts were produced and evaluated in the same manner as in Examples 1 to 10. The joint strength was inferior to when the styrene resin compositions (S1) to (S3) and (SC1) to (SC3) containing methacrylic acid monomer units were used. The evaluation results and calculated values ​​of each parameter based on each combination of resin parts are shown in Table 4.

[0148] [Table 4] [Industrial Applicability]

[0149] The dissimilar resin composite member obtained by the present invention has excellent strength, heat resistance, rigidity, and assembly cycle properties at heat-welded parts. Therefore, the dissimilar resin composite member of the present invention is useful for lighting housings and housings for automotive lights, particularly automotive rear lamp housings, and will play a major role in industry.

Claims

1. A heterogeneous resin composite member in which an acrylic resin member made of an acrylic resin composition and a styrene resin member made of a styrene resin composition having a Vicat softening temperature of 105°C or higher are welded together, The acrylic resin composition has a content of methyl methacrylate monomer units of more than 50% by mass, The styrene-based resin composition has a content of styrene-based monomer units of more than 50% by mass and a content of methacrylic acid monomer units of 3% by mass or more, The Hansen solubility parameter (HSP) value (δ dｓ , δ pｓ , δ ｈｓ ) (J / cm ３ ) １／２ and the Hansen solubility parameter (HSP) value (δ ｄａ , δ ｐａ , δ ｈａ ) (J / cm ３ ) １／２ ] is expressed by the following formula (1): [Equation 1] HSP distance={(d ｄs -d ｄａ ) ２ +(d) ｐｓ -d ｐａ ) ２ +(d) ｈｓ -d ｈａ ) ２ } １／２ ≦4.0 (In the above formula (I), δ ｄｓ is the dispersion force term of the styrene-based resin composition (J / cm ３ ) １／２ represents δ ｐｓ (J / cm ３ ) １／２ represents the polarity term of the styrene-based resin composition, and δ ｈｓ (J / cm ３ ) １／２ represents the hydrogen bond term of the styrene-based resin composition, and δ ｄａ is the dispersion force term of the acrylic resin composition (J / cm ３ ) １／２ represents δ ｐａ (J / cm ３ ) １／２ represents the polarity term of the acrylic resin composition, and δ ｈａ (J / cm ３ ) １／２ represents the hydrogen bonding term of the acrylic resin composition.

2. The polar term (δ) of the Hansen solubility parameter of the chloroform-soluble portion of the styrene-based resin composition ｐｓ ) and hydrogen bond term (δ ｈｓ ) and the sum is Sδ ｐ＋ｈ year, The polarity value (δ) of the Hansen solubility parameter of the chloroform-soluble portion of the acrylic resin composition ｐａ ) and hydrogen bond term (δ ｈａ ) and the sum of Aδ ｐ＋ｈ When this is defined as follows, the following equation (2) is obtained: [Equation 2] | Sδ ｐ＋ｈ - Aδ ｐ＋ｈ | ≤ 5.0... (Equation 2) The heterogeneous resin composite member according to claim 1 , which satisfies the above formula.

3. The heterogeneous resin composite member according to claim 1 or 2, wherein the absolute value of the difference between the Vicat softening temperature of the styrene-based resin composition and the Vicat softening temperature of the acrylic resin composition is 30°C or less.

4. The heterogeneous resin composite material according to claim 1 or 2, wherein the weight average molecular weight (Mw) of the acrylic resin composition is 70,000 to 300,000.

5. 3. The heterogeneous resin composite member according to claim 1, wherein the acrylic resin member has a total light transmittance of 90% or more in an optical path length of 2 mm.

6. 3. The composite member of different resins according to claim 1, wherein the styrene-based resin composition comprises a copolymer having styrene monomer units and methacrylic acid monomer units as a main component.

7. 3. The heterogeneous resin composite member according to claim 1, wherein the styrene-based resin composition has a lightness (L*) of 50 or less.

8. the styrene-based resin member having a recess; The composite member of different resins according to claim 1 or 2, further comprising: the acrylic resin member attached by welding near an edge of the recess.

9. The composite member of different resins according to claim 1 or 2, which is used as a lighting housing.

10. A rear lamp housing for an automobile, which uses the composite member of different resins according to claim 1 or 2.

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